Catalytic heater

ABSTRACT

A catalytic heating system comprising a main catalyst ( 20, 50 ) for flameless catalytic burning of fuel gas and a triggering system for initiating the catalytic burning, the triggering system comprising an electrical power source electrically connected to a metallic catalyst portion ( 104 ). As electric current flows through the metallic catalyst portion, it is in itself heated as an electric resistance heater to a temperature necessary for triggering the catalytic burning. By using electrical current for direct heating of a catalyst portion, reaction starts as soon as the resistance heating achieves the temperature for initiating the catalytic reaction. As soon as the reaction starts, it is transferred to the main catalyst.

FIELD OF THE INVENTION

The present invention relates to a catalytic heating system comprising amain catalyst for flameless catalytic burning of fuel gas and atriggering system for initiating the catalytic burning, the triggeringsystem comprising an electrical power source electrically connected toan electrical resistance heater for heating a catalyst portion to atemperature necessary for triggering the catalytic burning.

BACKGROUND OF THE INVENTION

Catalytic heating for hot water supplies is well known in the art anddescribed, for example, in U.S. Patent No. 4,510,890 by Cowan, U.S. Pat.No. 4,886,017 by Viani, and U.S. Pat. No. 5,709,174 by Ledjeff et al.Though, burning of fuel by combustion is easily started by a piezospark, it is very difficult to start by such simple means, especially ifthe system has small dimensions. In order for the flameless catalyticoxidation of the fuel to start, a temperature of typically 150° C. hasto be achieved first for the catalytic burning. Therefore, as a startingmechanism, one common method, as also described in U.S. Pat. No.5,709,174 by Ledjeff, is to burn fuel in a flame in a combustion chamberprior the catalytic process in order to provide initial heat to startthe catalytic process.

Using flame combustion as a starting mechanism for a catalytic heaterimplies a number of precautions to be taken. As the temperature formethane combustion reaches 1300° C., the chamber needs a relativelylarge size for not leading to damage in the adjacent heat exchanger.Therefore, typically, the combustion products are mixed with air inorder to reduce the temperature. The problem is described in U.S. Pat.No. 4,886,017 by Viani. A disadvantage of such systems may be seen inthe provision of a combustion chamber, Which makes it difficult toprovide small systems, for example portable systems, when using acombustion chamber. Another disadvantage is the fact that combustiononly starts if the oxygen content is between 2% and 9% in the case ofpropane or butane as fuel. However, this oxygen-poor mixture results inincomplete burning, such that the combustion products have a strongsmell, which requires that these burners also have an afterburner forburning the remaining fuel in the combustion gases.

All in all, this kind of systems are generally large and expensive andnot suited for portable devices.

An alternative starting mechanism is disclosed in U.S. Pat. No.4,886,017 by Viani, where an electrical resistance heater is embedded inthe catalyst material having between 0.01% and 10% by weight of acatalytic metal on a solid support material of divided form, for exampleceramics. This solution avoids the need of a combustion chamber and hasthe potential for small systems. However the need for heating theceramic based catalyst implies a rather strong electric source. If usedfor a portable system, which is interesting for hikers and militarypurpose, relatively heavy batteries limit the usefulness. It would bedesirable to provide a starting mechanism that can be made smaller forportable systems.

DESCRIPTION/SUMMARY OF THE INVENTION

It is therefore the object of the invention to provide a catalyticheating system with a starting mechanism that is easy to implement insmall systems having a minimum weight.

This object is achieved with a catalytic heating system comprising amain catalyst for flameless catalytic burning of fuel gas and atriggering system for initiating the catalytic burning, the triggeringsystem comprising an electrical power source electrically connected to ametallic catalyst portion. As electric current flows through themetallic catalyst portion, it is in itself heated as an electricresistance heater to a temperature necessary for triggering thecatalytic burning.

The term catalyst portion means a portion of a catalyst, thus thecatalyst portion itself is made of an electrically conducting, metalliccatalytic material, for example the same material as the main catalyst.By using electrical current for direct heating of a catalyst portion,reaction starts as soon as the resistance heating achieves thetemperature for initiating the catalytic reaction, because the oxygenenriched fuel gas is in direct contact with the heated catalyst. As soonas the reaction starts, the reaction is transferred to the maincatalyst.

In contrast to prior art document U.S. Pat. No. 4,886,017 by Viani,there is no need for heating a non-catalytic electric resistance heaterfirst and then transferring the heat to the catalyst. Especially inconnection with prior art, if the main component of the catalyst isceramics, as in U.S. Pat. No. 4,886,017 by Viani, there is a need forrelatively large amounts of current in order to provide enough energyfor the reaction to start. In contrast thereto, according to theinvention, no heat transfer is necessary to any catalyst, as thecatalyst portion itself is heated by the current. This implies that onlyrelatively small amounts of current are needed for the triggeringprocess, especially if the catalyst portion is small. The advantagethereof is that power supplies in the fowl of batteries/capacitors canbe made smaller and lighter without compromising the endurance of thebatteries, which is advantageous in especially portable systems.

A flameless catalytic heating element—without initial flamecombustion—implies a reduced danger when being operated in dangerousareas with flammable or explosive gases or steams, such as chemical orpetrochemical storing sites and places. A flameless catalytic heatingelement can also be safely operated in areas with highly flammable dustor metal dust and in building areas, where gas-powered vehicles arebeing maintained, stored or parked.

The catalyst portion may be part of the main catalyst. However, this isnot necessary. The catalyst portion can be a separate unit fortriggering of the reaction which, then, is transferred to the maincatalyst. This makes the triggering portion independent of the maincatalyst, which may be made of metal, for example platinum, palladium,rhodium, ruthenium or iridium, and/or which may be made with anon-metallic support, for example activated alumina, silica, orceramics.

In order to reduce the electrical power consumption during thetriggering, it is advantageous if the metallic catalyst portion issubstantially smaller than the main catalyst. For example, the metalliccatalyst portion through which current flows has a size of less than 1cm, preferably less than 1 mm. In a practical embodiment, the metalliccatalyst portion is a metal mesh, and the size of that part of the meshthrough which current is flowing for the triggering is between 0.1 mmand 0.5 mm, for example around 0.25 mm. The term “size” covers anydimension, that is the length, width and height, of that part that isheated to the temperature at which the reaction starts. For example, ina practical embodiment, current is flowing through a mesh wire, wherethe mesh wire has a thinner catalyst portion than the rest of the meshwire. The thinner catalyst portion is heated up to the triggeringtemperature of around 150° C. first and starts the catalytic processwhen the mesh wire has contact with the oxygen in the oxygen enrichedgas/air mixture which raises the temperature to a higher temperaturelevel which is necessary for start of the process.

A preferred embodiment comprises a main catalyst being a metallic mesh,because IR radiation can traverse the openings in the mesh and leads toa better heat distribution. Such a mesh may be a thin mesh which isarranged in a flat configuration or bent, for example bent into a tube.For example, such a tube may be provided with a cross section that iscircular, oval, or polygonal. The tube formed mesh has the advantagethat IR radiation inside the tube easily escapes through the openings inthe mesh, which allows for use of the tube formed catalyst to heatliquids in a tank surrounding the catalyst. As the catalyst does notneed to surround a liquid tank but heats the liquid form an internalposition with respect to the liquid tank, the catalyst heater accordingto the invention can be constructed compact, which is especially usefulin portable devices.

In a further preferred embodiment, the main catalyst is a tubular meshformed with varying cross section. In this case, it is an advantage toprovide the gaseous fuel to the narrow part of the main catalyst. It hasbeen observed in an experiment with a catalyst shaped as a truncatedcone that a reduction of the supplied gaseous fuel reduces the catalyticburning to the narrow part of the truncated cone shaped catalyst, wherethe gas is supplied. If the supply of gaseous fuel is increased into thecatalyst, the catalytic burning is distributed gradually also to thepart with the larger cross section. This yields a smooth regulationmechanism for the desired heating efficiency.

A certain experiment used a conical catalyst in a cylindricalfluid-proof, infra-red transparent enclosure immersed in a liquid tank.The conical metallic mesh catalyst was provided with the large endtowards a bottom of the enclosure and the narrow end of the cone wasarranged towards the gas exhaust. It was observed in this experimentthat this arrangement yielded a higher efficiency for the catalyticburning and heat transfer than in an embodiment with a cylindricalcatalyst in a cylindrical enclosure. The reason for this is not fullyunderstood but believed to be due to a better transport of emissiongases. Preferably, the gas itself is blown into the upper narrow part ofthe conical catalyst in the direction of the wide end of the cone.

In a further embodiment, the catalytic heating system comprises aventuri system for mix of fuel gas and oxygen before the catalyticburning. The venturi system comprises a venturi nozzle with a nozzleexit and a channel surrounding the venturi for provision of oxygen, forexample provided in an air stream through the channel. The exit of gasfrom the venturi nozzle pulls air or oxygen along the gas stream inorder to provide a blend of gas and oxygen or gas and air. A venturisystem is robust and dependable and may be manufactured in a greatnumber for low costs, which for a system is a great advantage because isconsidered to be distributed among many users.

In experiments, good results have been achieved, if the channel formedbetween the outer wall of the venturi nozzle and a pipe portionsurrounding the nozzle is provided by an outer concave wall of theventuri nozzle and a convex pipe portion around the venturi to form asmoothly bending channel towards the venturi nozzle exit. By this means,a smooth flow of air was achieved resulting in a high efficiency of thecatalytic burner.

The venturi system just described may also improve prior art systemswithout the need of the triggering catalytic portion. The advantage liesin the fact that a high amount of oxygen can be supplied to the fuel gasresulting in an efficient catalytic burning. Experiments have shown thatthe achieved efficiency with such a venturi can be near theoreticalvalues. In other words, a catalytic heater with a catalyst and a fuelgas supply may on a general basis take advantage of having a venturisystem between the gas supply and the catalyst for mixing the fuel gaswith oxygen from an oxygen supply, for example in the form of air.Especially advantage is the venturi system with the concave wall of theventuri nozzle and a convex pipe portion around the venturi to form asmoothly bending channel towards the venturi nozzle exit.

Catalysis occurs in the temperature range 370-425° C. These temperaturescorrespond to IR wavelengths about 3-7 μm, which basically coincidingwith the maximal absorption spectrum of water, which is in the range of3-7 μm. Consequently, IR heating is well suited for heating of water orwater containing liquids. For embodiments intended to be immergeddirectly into the medium to be heated, there has to be provided awater-proof separation between the medium to be heated and the catalyticheating element. In order to enhance the efficiency of the transmissionof the IR radiation it is advantageous to provide a partition wall madein a material that can be optimised with regard to both transmission ofIR radiation and transfer of convection heat. For example, the partitionwall may comprise aluminium, copper or quartz glass or a combination ofthese.

A preferred portable embodiment of the invention has an integrated fueltank. This fuel tank may be a refillable fuel tank or an exchangeabletank, for example screwed unto a corresponding winding and with a tubeconnection to the heater. Optionally, this fuel tank can be integratedin a handle or constitute a handle by itself. In the case of a portablesystem, the device may comprise a handle with a heating pipe containingthe catalyst arranged in extension hereof. The heating pipe is producedin a material that is transparent for infra-red radiation andfluid-proof for immersion in liquids.

When fuel gas is extracted from a fuel tank with liquid fuel, theevaporation of the liquid into a gas causes a temperature drop in thefuel tank near the exit of the fuel tank. This can lead to a limit forthe rate at which gas can be extracted from the gas tank, especially ifthe surroundings, where the heater is used, are cold. In order tocounteract this reduction of the extraction rate, there may be provideda heat exchanger between the fuel tank and an exhaust pipe system forheat exchange between emission gas from the catalytic burning and a wallof the fuel tank. As the emission gas from the catalytic burner is hot,this heat energy can be used to heat the tank. By keeping the gaspressure and gas flow speed high, it is assured that a venturi systemcan work efficiently and add the necessary amount of oxygen/air for thecatalytic process.

For use in the military, the portable heating system has the advantagethat it is more difficult to trace in use than conventional heatingmethods. The heating system does not have any form of visible flame. Thesystem layout secures that the portable heating unit is surrounded bythe medium, which has to be heated, which acts as a shield for the heat.Furthermore, the emission gas is cooled efficiently by transferring heatto the gas tank. Also, the air providing oxygen for the catalyticburning is heated by the emission gas. This has triple advantage: 1) theair intake gas is heated for an efficient catalytic burning, the gastank is heated for gas extraction at a higher rate, and the exhaust gasis cooled, which reduces the traceability of the system, which iscrucial in military operations. Accordingly, there is only a weakthermal profile in use. The concept layout secures furthermore, that thesound level is very low and that no smoke is formed. Furthermore, theefficient burning from the onset without a flame combustion chamber as astart mechanism reduces smell from unburned fuel of the system to aminimum.

Due to the high efficiency, which is more than 3 times better than theoff grid heating systems with cooking vessels and pots used today, thisheating system is both energy-efficient and environmentally benign. Theenergy consumption is very low, namely only about 10-12 gram gas perlitre water heated from 20° C. to 100 ° C. By way of example, apropellant as natural gas, propane gas, butane gas, isobutene gas or amixture hereof is being used. According to all prognoses, it should bepossible to supply butane gas for the next 100 years. Heating units mayin practice also apply hydrogen as propellant without significantchanges.

The heating system has proved to heat water to the boiling pointreliably even under extreme weather conditions including very lowtemperature and strong winds. Therefore, it is suited for militarypurpose and extreme sport.

In another embodiment, the catalyst is elongate and extends horizontallyor substantially horizontally in a bottom area of a liquid tank. Forexample, the catalyst is tube formed, as described above and arrangedinside a water-tight and IR transparent tube. In order to direct the IRradiation in a certain direction, an IR mirror may be provided.

Alternatively, the catalyst is sheet formed and contained in acorresponding water-tight and IR transparent enclosure.

The invention is useful for a large number of uses, for example in thecase of a portable, off-grid heater system,

-   -   Heating of water—scalable    -   Heating of pools    -   Heating of infusion fluids/intravenous fluids/blood    -   Personal body heater    -   Sterilization of surgical instruments    -   Heating of milk/food for babies    -   Catalytic cooking plates—IR    -   Portable oil radiators    -   Central heating garments—extreme sporters, outdoor workers,        rescue workers, first responders,    -   Off grid autoclave    -   Heating of water in petrochemical environments    -   Weed burner and in the case of using the catalytic burner in        connection with a gas refrigerator principle    -   Cooling garments—extreme sporters, outdoor workers, rescue        workers    -   Cooling of fluids, for example water, infusion fluids,        intravenous fluids, or blood

In the case of an on-grid application

-   -   Heating of water—petrochemical areas/offshore/boats    -   Heating of pools    -   Portable oil radiators    -   Water heaters and boiler for central heating    -   Catalytic LPG stoves    -   Booster for heating of houses

In connection with catalytic heaters, especially off grid portablesystems are challenging to construct, in as much as a long catalyticburning chamber requires a large diameter in order to be possible toignite with a spark. For a certain length to width ratio, sparkignition, for example by a piezoelectric crystal, may be successful forlarge systems, but fail for small systems. Experience from large systemswith respect to ignition of the catalytic process seems not to bescalable to small systems. This is surprising but has led to theignition approach according to the invention.

A preferred embodiment is a flameless catalytic burner with a ratiobetween the diameter and the length is larger than 4. Further, it ispreferred that the burning chamber is closed for immersion heating ofliquid. especially in the case of a portable off grid device.

A preferred embodiment is a catalytic heater with a closed burningchamber for immersion into liquid and with a gas fuel supply through aventuri for adding between 1% and 9% air which is optimum for catalyticburning. In a vertical orientation of a tube formed burner, exhaustgases will seek upwards and leave the heater analogous to exhaust gas ina chimney. If the chamber has a diameter of less than 38 mm, and alength of about 160 mm, which are suitable dimensions for portablesystems, it has turned out that such a device cannot be ignited by aspark. Therefore, the ignition system with an electric heater being acatalyst itself is ideal for such a system.

Preferable dimensions for portable systems are diameters of the burnerof between 10 and 50 mm, preferably between 30 and 40 mm, and lengthsbetween 50 mm and 300 mm, preferably between 100 and 200 mm.

A prototype has been fabricated along these lines with a total weight ofless than 200 grams, an efficiency of more than 70% yielding an effectof 650 W, which is the approximate heat capacity of a ceramic heatingplate with a nominal effect of 1600 W. The heat effect of a burner withan inner diameter of 22 mm and an outer diameter of 24 mm, and a lengthof 130 mm was measured to 16.5 W/cm². It was able to start in atemperature of −40° C. without problems.

As mentioned above, in order to provide fuel for a catalytic burner, agas supply is inserted into the burner, such as a gas cartridge. Suchcartridges are commercially available for example from the companyBraun®, which also commercially supplies curling irons. Such cartridgesare supplied with an internal seat valve for delivery of gas from thecartridge, when a tube member of the seat valve is pressed into thecartridge by a stem.

In order to provide an even flow of gas from cartridges, there aretypically provided pressure valves in prior art apparatuses. Constantflow valves are described in the prior art patents documents mentionedabove. In order to vary the flow for keeping a constant temperature,bimetallic valve elements may be applied. Such regulation is necessary,in as much as a seat valve in a cartridge according to the prior artprimarily works as an on-off valve and is very difficult to adjust.However, these regulation systems are rather expensive solutions.

A better solution is given by a gas cartridge having a built-in gas flowadjustment mechanism that can be produced at low cost as described inthe following. This cartridge can be used as part of the inventiondescribed above but also can be provided independently thereof for otherpurposes, mainly catalytic burners, however.

The cartridge for gas with or without aerosols comprises a container forcontaining the gas and comprises a valve arrangement for release of gasfrom the container. The valve arrangement comprises a valve, for exampleseat valve, with a tube member and a resilient member providing aresilient force against the tube member in a direction away from thecontainer. The tube member has an inner channel between a first openingdirected towards the outside of the container and a second openingdirected towards the inside of the container for release of gas from thecontainer through the channel when the tube member is pressed againstthe resilient force a distance along a pressing direction towards theinside of the container.

Optionally, the tube member has a tube wall around the channel with aplurality of second openings interspaced along the pressing directionfor release of gas through a selection of these openings in dependenceof the distance by which the tube member is pressed towards the insideof the container. For example, the second openings have mutually varyingcross sectional sizes. Optionally, the tube wall is cylindrical with thefirst opening at the first end with an opposite closed end.

By varying the cross section and/or the number of the used openings forthe gas release, there is provided a simple stepwise adjustable valveinto a cartridge. Thus, it is possible to tune the gas flow—with orwithout aerosols—without the necessity of having a complicated valvearrangement in the apparatus, into which the cartridge is inserted. Asthe apparatus into which the gas cartridge is inserted does not need anycomplicated or dedicated valve arrangement, any correspondingmaintenance work is avoided for the user. If the valve is not functionproperly, the cartridge can be exchanged with another cartridge. Asthese cartridges are mass produced, the costs are low.

Preferably, the tube wall of the tube member is surrounded by aresilient polymer gasket, typically a sealing ring, which tightens thesecond openings against the gas pressure from the container. Inpractice, this may be achieved by locating the openings on that side ofthe gasket which is facing away form the container. When the tube memberis pressed towards the container, one opening after the other is pushedto the opposite side of the gasket allowing gas to be released throughthese second openings. In the most preferred embodiment, all theopenings that have been pushed to the opposite side of the gasket allowgas to flow into the openings.

Alternatively, the pushing of the tube member in the pressing directionmay open only a selection of openings, possibly only one opening at atime, and close all neighbouring openings by second gasket means. Thelatter is relevant, if the openings have different cross sections, forexample, such that the first opening is used for a first flow rate andthe next opening is used for a second, higher flow rate.

It is an option that the cartridge is a replacement cartridge, which isreplaced by another cartridge when emptied and not filled with new gason site. However, the cartridge is advantageously part of a recyclingsystem, where the cartridge is refilled for re-use at a recyclingfactory. As a step in this recycling procedure, the cartridge is alsotested for proper functioning of the valve arrangement, preferably aseat valve. This testing can easily be automated such that only minorcosts arise for this testing step in the recycling process. It should bestressed at this point that the production costs of a cartridge isalmost negligible as compared to commercially available prior artcartridges.

For military use, it is of importance that the risk for explosion of acartridge for the catalytic burner is minimised also with respect to thepossibility of being hit by a bullet. This minimising of the risk isachieved by providing the cartridge with a low friction surface, forexample a polytetrafluorethylene (PTFE, Teflon) surface. In case thatthe cartridge is hit by a bullet, the low surface friction minimises theheat that is developed on the surface due to the bullet sliding alongthe surface during deformation. If the heat production due to the lowfriction is low, the gas may be prevented from ignition and explosiondespite the fact that the bullet penetrates the cartridge wall.

Cartridges used for gaseous fuel, such as for catalytic burners, maycomprise a tube extending from the valve arrangement and into the middleof the container. If the cartridge is filled with liquid gas only toless than the middle height of the cartridge, liquid gas cannot flowinto the tube, not even when the cartridge is turned upside down.However, shaking of the apparatus with the cartridge during gas releasemay cause liquid gas to find its way into the tube, and proper gasrelease is disturbed. As a countermeasure, the cartridge in a furtherembodiment comprises a fibrous absorptive material for absorbing liquidgas. Optionally the fibrous material contains cellulose based fibres orcotton or both. Alternatively or in addition, polymer fibres may becontained. First experiments have used a simple, typical, commerciallyavailable prior art tampon, which has proved highly satisfactory for thegas absorption purpose. Though not strictly necessary, the fibrousabsorptive material is advantageously combined with a cartridge-insertcombination according to the above.

Typically, gas cartridges are provided with a screw thread for fasteningof the cartridge to the apparatus of interest. Such screw threads arestandardized and only very few variants are available due to the lownumber of mass producers. This implies that an apparatus using thesecartridges has to be designed with one of these standardized threads orwith means for fastening of cartridges without threads at all. Theserequirements limit the degrees of freedom for the design of such anapparatus.

Thus, it would be desirable to have a greater variation of fasteningmeans such that there is greater freedom with respect to apparatusdesign. In other words, it would be desirable to provide a solution fora gas cartridge for having greater variety of screw connections. This isachieved with an insert for a gas cartridge, the gas cartridge having avalve arrangement for release of gas with or without aerosols from thecartridge. The cartridge has first fastening means and the insert hassecond fastening means configured for cooperation with the firstfastening means for fastening the insert to the cartridge around thevalve arrangement. The insert has a screw thread for screw connectionwith a gas consuming apparatus.

By such an insert, gas cartridges can be provided with screw threadsadapted to the apparatus of interest. For example, such an insert may beused in connection with the cartridges having a stepwise adjustmentmechanism as described above, however, it may also be used any otherkinds of suitably dimensioned cartridges, for example for prior artstandard cartridges without stepwise regulation.

By selecting a screw thread dimension which is different from prior artcommercially available threads, it is prevented that the cartridge isused for other apparatus than designed with a corresponding thread. Inturn, if an apparatus is provided with a certain thread, only thosecartridges can be used that have a corresponding thread in the insert.Thus, the manufacturer of a specific apparatus needing a certain type ofgas or gas+aerosol mixture may order a number of cartridges with thedesired content, and may provide these with inserts of a kind that onlymatches the special thread of the specific apparatus. Thus, thecartridge itself may become a new production standard, whereas theinsert may be selected in dependence of the desired content and/or independence of the manufacturer or specific apparatus. This implies thata fuel gas cartridge may be provided with a different thread in theinsert, for example a larger thread, than an aerosol cartridge, by whichno accidental and possibly risky mismatch between the apparatus inquestion and the corresponding cartridge occurs. Thus, the system withthe insert has a potential for a pronounced increase in safety for theuser.

The cartridge may be produced with a cavity around the valvearrangement, the cavity having a side wall widening in an inwarddirection of the cavity so as to form a shoulder in the cavity. Forexample, such a shoulder is formed during a press-mounting of a closuremember with the valve arrangement onto the rim of a container, where theside walls of the closure member are deformed. Thus, no specialproduction action is required for producing these shoulders, becausecommercial cartridges are already provided with such a circular shoulderalong the rim of the cavity. Thus, such a cartridge can relatively easybe included in today's production processes. Typically, the insert wouldhave an overall cross section similar to the cavity. In a preferredembodiment, the insert has resilient wings for fastening the insert tothe cartridge by a clip action of the wings under the shoulder.

Commercially available cartridges have a seat valve with a tube memberfrom which gas can be extracted when the tube member is pushed partlyinto the container. In order to protect such tube members, the insertmay have a central protection cap for covering a gas exit of the valvearrangement.

Preferably, the insert has a substantially circular cross section with arim part comprising the wings and the screw threads, which preferablyare directed inwards. Advantageously, the protection cap is connected tothe rim part by a plurality of bars configured for manual breaking torelease the cap from the rim part. These bars imply a safety signal forthe user, because the cartridge can only be used without the cap, and abreakage of the bars for removal of the cap clearly indicates for a userthat the cartridge has been used before.

When the insert is inserted into the cavity of the cartridge, and thecartridge with the insert threads is screwed onto a cooperating threadof an apparatus, screwing of the cartridge relatively to the apparatusmoves the cartridge towards or away from the apparatus. If the apparatusis equipped with a static counterpart pushing against the tube member,the turning also moves the tube member in or out of the cartridge foradjustment of the flow.

As has turned out during experiments, a threading of 0.5-1.0 mm impliesa good modulation and touch with the flow adjustment.

The cartridge is especially suited for a heating apparatus with acatalytic burner. For example, the heating apparatus has an enclosurefor enclosing the cartridge. When the cartridge is emptied to run thecatalytic burner, the shift of the fuel from the liquid phase to the gasphase may lower the temperature of the cartridge. In addition, also coldenvironments may result in a low temperature of the cartridge such thata proper flow out of the cartridge is no longer guaranteed. In order toimprove this situation, the heating apparatus may have a flow pathleading the burned gas from the catalyst past the cartridge, therebyproviding a heat exchanger arrangement in the enclosure around thecartridge for heat exchange between burned gas from the catalytic burnerand the cartridge surface. This reduces also the temperature of theexhaust gas, which may be a great advantage to reduce the thermal(infrared) traceability of the heater in military operations.

For reducing this traceability further, in another embodiment, theenclosure also houses a flow path for the intake air for the catalyticburner, the enclosure comprising a heat exchanger for heat exchangebetween the hot, burned gas from the catalyst and the intake air for thecatalyst. Thus, the emission gas is cooled from the hot stateimmediately after the catalytic burning at more than 400° C. to a coolstate only slightly above ambient temperature.

For reducing this traceability even further, the envelope may have gasrelease openings for release of burned gas to the surrounding atmosphereafter heat transfer from the gas to the surface of the cartridge, wherethe release openings have radially outwards directed flow paths. Theterm radially outwards has to be understood relatively to a cartridgehaving a cylindrical shape. Experimentally, it has been verified thatthe mixing with surrounding air is more efficient when the flow isradial as compared to a flow, where the emission gas is directedparallel with the cylindrical surface of a cartridge.

Such a catalytic heater is especially useful for military application,pre-hospital environments, and field hospitals, for use during hiking,trekking or camping, for heating of water or food, and for use as awarmer for parts of the body. The use for a curling iron is alsopossible among a large variety of other applications.

A preferred embodiment for catalytic burners, as already describedabove, comprises a catalyst being a metallic mesh, because IR radiationcan traverse the openings in the mesh and leads to a better heatdistribution. Such a mesh may be a thin mesh which is arranged in a flatconfiguration or bent, for example bent into a tube.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail with reference to thedrawing, where

FIG. 1 show a sketch of a portable heating system according to theinvention,

FIG. 2 illustrates a portable system in more detail,

FIG. 3 illustrates a heating unit in a bottle, a) covered with a lid andb) with a fuel tank installed

FIG. 4 illustrates a portable pressurized sterilizer a) closed with alid and b) with a heating unit inserted,

FIG. 5 illustrates a catalyst with plane straight units in a) end viewand b) side view,

FIG. 6 illustrates a catalyst with plane straight or plane bent units,wherein a) shows a straight unit, and b), c), and d) show different bentunits, and e) is a straight double catalyst,

FIG. 7 illustrates an embodiment with a conical catalyst mesh,

FIG. 8 illustrates an embodiment for a warm water supply with a conicalmesh catalyst,

FIG. 9 illustrates a portable flexible liquid heater bag,

FIG. 10 shows a portable infusion heater,

FIG. 11 illustrates a body heater,

FIG. 12 shows an embodiment for a triggering system in a heater systemand with a venturi system for a heating system according to theinvention,

FIG. 13 shows a gas cartridge in a side view a) before insertion of aninsert, and b) after insertion of the insert;

FIG. 14 shows the cartridge in a transparent view a) before and b) afterinsertion of the valve cup;

FIG. 15 shows the valve cup in greater detail;

FIG. 16 shows the cup insert in a) a cross sectional side view, b) in anend view with the protection cap, and c) in an end view with removedprotection cap;

FIG. 17 shows the valve cup with inserted cup insert and adapter;

FIG. 18 shows an assembly sequence a) before and b) after insertion ofthe valve cup into an adsorptive media, c) before and d) after insertionof the adsorptive media with the valve cup into the container, and e) inan end view;

FIG. 19 shows the cartridge inserted into an apparatus in a) crosssectional side view and b) in an enlarged partial view;

FIG. 20 shows an alternative embodiment with a tube around the cartridgein the apparatus in a) an overview and b) partially stripped enlargedview;

FIG. 21 illustrates a heater with passive flow adjustment,

FIG. 22 illustrates a heating system for the cartridge.

DETAILED DESCRIPTION/PREFERRED EMBODIMENT

FIG. 1 shows a heating system 1 according to the invention. The heatingsystem 1 comprises a heating unit 2 and a protecting container 163. Theheating unit 2 has a handle 4 for attachment of the heating unit 2 and aheating pipe 5 that emits heat radiation from the catalytic elementcontained in the heating pipe 5. The heating pipe 5 can be fitted into aprotective container 163, when the heating system is not in use. Thecontainer 163 may also be used for storing fluids or other materialssuch as powder, for example in connection with heating with the heatingpipe 5 or in order to constitute a storage container of fluid or othermaterials during transport and use. The container 163 may be used forhot fluids and function as a thermo-isolating bottle or for warminghands by holding the container 163. The container 163 may be thermallyisolated in order to reduce the output of energy to the surroundings.

The container 163 has an upper opening 6 and a thread 7 corresponding toan internal thread (not shown) of an adapter 8 in one end of the handle4. FIG. 1 a shows the heating unit 2 and the container 163 separatedfrom each other, while FIG. 1 b shows the heating unit 2 and thecontainer 163 in a situation, in which they are screwed together.

It should be noted that the container 163 may have other shapes andsizes than the one shown in FIG. 1, and the heating system 1 may beprovided with a number of other containers for heating of fluids orother materials. It would be beneficial to provide such other containerswith an internal or external thread 7 in their open end 6, so that theymay be screwed together with the adapter 8 for heating of the materialtherein. In connection to heating of fluid or another material in thecontainer 163, it is up to the user to take into account any pressurerise in the closed tank that could occur during the heating. In order toprevent damage to the material and/or the personnel in case ofover-pressure in the container 163 due to the heating, the heatingsystem 1 may advantageously be provided with a safety valve connected tothe interior of the container 163, in order to provide a passage forequalization of pressure relative to the atmosphere in case ofover-pressure in the container 163. It is not necessary that afluid-filled tank is screwed together with the adapter 8 during theheating process.

The heating system 1 may, near the handle 4, furthermore, be providedwith a pivotal hanger 9 for attachment of the system 1, for example in abelt on a uniform.

The heating pipe 5 is closed at the lower end in order to prevent fluidfrom entering the pipe 5. Accordingly, there is no entry of fluid fromthe container 163 into the handle 4 or into the pipe 5. The safety valvefor equalization of pressure may also be located in the adapter 8.

In the pipe 5, there is installed a catalytic burner in the form of ametallic mesh that is supplied with gas to the process from a fuel/gastank in the handle 4. Between the gas tank and the catalytic burner inthe pipe 5 there is provided a valve, which can be controlled by use ofa regulator via a button 11 or a build in valve in the fuel tank. Inorder to make the catalytic process start, it is necessary to heat thecatalyst. This can be done by pushing a push button 10 as shown in FIG.1 b. The push button 10 both provides electricity to the catalystportion that ignites the flameless catalytic burning and opens for thegas so that the heating unit 2 may be operated with one hand. Airsuction and exhaust of gas is provided via openings in the upper part ofthe handle, in which there in FIGS. 1 a and 1 b is shown the air suctionopening 12, while the exhaust opening on the opposite side of the handleis not shown in this figure. Such suction openings 12 and exhaustopenings may be provided with a regulation valve 13 for regulation ofthe volume of intake air and emission gas, respectively, through theopenings.

In FIG. 2 is shown a specific embodiment of the more general heatingsystem 1 shown in FIG. 1. The sketch in FIG. 2 shows the handle 4 withthe heating pipe 5 inserted into the built-on container 163. The handle4 comprises a fuel/gas tank 14, from which gas via a regulator 15, forexample operated by a button 11 as shown in FIG. 1 a, is fed into anozzle 16. Such nozzle 16 is part of a venturi system 17, so that thegas carries air and hence oxygen along with it, when the gas is feed outof the tank 14. This air is provided via the pipeline 18 that isconnected to the inlet port 12. The gas and air mixture is feed througha transport pipe 19 between the venturi system 17 and a catalyticelement 20. The transport pipe 19 is on the same level as the catalyticburner 20, which may be provided with apertures or an adjusted length ininteraction with a special shaped bottom that forms the closing sectionof the catalytic element 21 in order to ensure a smooth flow and gas-airdistribution in the catalytic burner 20. After the catalytic process, inwhich the fuel gas is converted to carbon monoxide and water vapour,these emission gases are feed through another pipe system 22 to anexhaust opening 23 in the opposite section of the handle 4.

The catalytic burner 20 can have different geometrical shapes dependingon the intended application and efficiency. As an example, it maycomprise or be comprised of two plane units or of one or more curvedunits, for instance cylindrical units, which is illustrated in moredetail in FIGS. 5 and 6. FIGS. 5 a and 5 b illustrate end view and sideview of a heater system 30 inside which a plane straight catalyst 31arranged in a liquid tight enclosure with flat enclosure walls 32 and 33through which IR radiation is emitted to both sides. The system has anair inlet 34 and a gas exhaust 35. In order to provide an even flow ofinlet gas/air mixture, there is provided a manifold with multiple inlets36 in the lower part 37 of the heater system.

Alternatives for plane catalysts are illustrated in FIG. 6. FIG. 6 a isa sketch of the plane straight catalyst 31 with air inlet 34 and gasexhaust 35. FIG. 6 b illustrates a plane curved catalyst 38 forming abending of a half circle, whereas FIGS. 6 c and 6 d illustrate planecatalysts 39, 40, 41 with a bending over larger angles. A doublestraight plane catalyst 42 with is illustrated in FIG. 6 e.

With reference to FIGS. 1 and 2, the catalytic process produces a greatamount of infra-red radiation, which is being transmitted through thematerial of the heating pipe 5 and into the container 163, which isclosed upwardly with a partition wall 29. The medium in the container163 is being exposed to the infra-red radiation that especially heatsthe water in the container 163. In order to ensure an effectiveutilization of the infra-red radiation, the container 163 may beprovided with a reflective coating on the inside, in order to reduce theemission of heat through the wall of the container 163. It isfurthermore possible to construct the container 163 with a general heatinsulating wall, optionally with a multi-layered structuring as knownfrom thermo-isolating bottles and cans.

With a heat insulating container 163 and a handle that is not heated, itis difficult to trace the use of such heating system 1 in relation tomilitary actions, because the emission of heat, by this way, isminimised. A certain kind of emission of heat implying a potential riskfor tracing during application is associated to the heated emissions(gas, water vapour) from the known catalytic process through the exhaustopening 23. To reduce the temperature of the emission gases, there isprovided a counter flow heat exchanger 25 that, at least in part,encloses the gas tank 14 in order to transform heat from the exhaustemissions to the walls of the gas tank and further to the gas exit ofthe gas tank and to the liquid gas inside the gas tank 14. Moreover, thepipeline 22 for the emission gas is, at least in part, surrounded by thepipeline 18 for the intake air through the inlet port 12. Accordingly,heat is transferred from the emission gases to the gas tank 14 and tothe intake air, which contributes towards an optimal catalyticcombustion. In this connection it should be mentioned that the gas fromthe gas tank 14 during expansion after the nozzle 16 in the venturisystem 17 entails a cooling of the gas which increases the uptake ofheat from the emission gas. Emission of heat from the emission gas tothe intake gas and the gas tank 14 contributes towards to ensure anexpedient function of the heating system 1 also in very coolsurroundings. Therefore, the heating system 1 is well suited for useboth in hot and cool areas, and due to its robust nature, it is wellsuited for use in the military sector.

In the case of heating of water, food or another medium 24 in thecontainer 163, when it is mounted on the adapter 8, a possibly generatedover-pressure in the container 163 due to the heating induces a risk forthe heating system 1 and for the user of it. In order to reduce the riskfor damage of the apparatus and the personnel, the heating unit 1 isprovided with a safety valve 25 between to the interior of the container163 and the atmosphere outside the tank. The safety valve opens apassage between the interior of the container 163 and the surroundingatmosphere for equalization of pressure. The over-pressure valve is inthe figure located in the adapter 8, but it is possible to provide aover-pressure valve in other appropriate places in the apparatus.

To be even easier to operate, the heating unit 2 may, furthermore, beprovided with a heat sensor 26, which by use of the infra-red radiationemitted by the medium 24 can measure the temperature of the medium 24.Alternatively, such heat sensor 26 may comprise a thermometer thatmeasures the temperature of the medium while being submerged into themedium. However, this embodiment is not shown in FIG. 2. The heat sensormay be connected to a temperature indicator on the handle (not shown) orto an acoustic device that indicates when the medium 24 has reached acertain preset temperature. It may, as an example, be possible to setthis temperature on a unit on the handle or the temperature may bepreset, so that it is indicated when a certain temperature is reached,for instance by a sound or light indication on the handle. Hence, it mayalso be considered to use installed light indicators in differentcolours or a number of light indicators that are turned on depending onthe temperature reached in order to indicate to the user the temperaturereached or exceeded.

As a further alternative, a temperature dependent valve that regulatesthe gas flow directly to the catalytic burner may be inserted. If thetemperature in the catalytic burner exceeds a preset temperature, thistemperature dependent valve will regulate the gas flow downwards untilthe temperature come down below the level that is permitted in thecatalytic burner.

FIG. 3 b shows a bottle 95 with an inserted heating unit 2 having a fueltank 14 and a heating pipe 5. An overpressure valve 92 prevents damagedue to overpressure in analogy with the above mentioned embodiments.When the heating unit 2 is not in use, the fuel tank 14 may be removedand the remaining heating unit with the heating pipe 5 covered by a lid89, as illustrated in FIG. 3 a. The heating unit is connected to thebottle 95 by a standard adapter 8 as mentioned in connection with theother embodiments.

FIG. 4 a and b illustrate a portable pressurized sterilizer 96 with apressurisable container 97 closed with a pressure resistant lid 98,which is opened to insert medical tools or other effects to besterilised. Optionally, these tools may be placed into a grid which isinserted into the container. When not in use, as illustrated in FIG. 4a, the container 97 is closes by another lid 89. This other lid 89 isremoved, when a heating unit 2 is inserted into the container 97, whichis illustrated in FIG. 4 b. Alternatively, the heating pipe 5 may resideinside the sterilizer, and only the fuel tank 14 is removed for placingthe another lid 89. In order for the sterilizer not to explode, theheating unit 2 is provided with a pressure valve 92. This overpressurefor the valve to open may be adjusted to a predetermined value, forexample 2 bars.

In fact, a portable pressurised sterilizer is generally useful whencombined with catalytic burners, also if the burners have other ignitionsystems than the present invention. For example, a piezoelectricignition system or a system as disclosed in U.S. Pat. No. 4,886,017 byViani could be used alternatively. Thus, useful is a portablepressurised sterilizer with a pressurizable container having an openingfor insertion of elements to be sterilized and with a catalytic burnerimmersed in a liquid inside the container. Preferably, the catalyticburner has a heating pipe containing the catalyst, where the heatingpipe is produced in a material that is transparent for infra-redradiation and fluid-proof for immersion in liquids. Such a catalyticheater may be fastened to an opening in the container for submersing theheating pipe into the liquid in the container, where the openingcooperates with an adapter of the catalytic burner in order to achieve atight fastening, for example a screw fastening.

FIG. 7 illustrates an embodiment with a conical catalyst. Thisembodiment comprises a conical main catalyst 50 connected to a gassupply tube 51 at the narrow end of the cone for release of fuel gas andair mixture in the upper end of the conical main catalyst 50. The gas isreleased under pressure, which transports the gas to the lower, wide endof the cone, where also a trigger mechanism with a catalyst portion 52is located. Gas is supplied through a gas inlet 53 via a gas flowregulator 54 and a venturi system 55, where gas and air from the airinlet 73 is mixed. For the triggering, the flow regulator opens forgas/air supply into the lower end of the main catalyst tube 50 andswitches electrical current in wire 56, which is electrically connectedto the catalyst portion 52. The metal catalyst portion 52 in the bottompart of the main catalyst tube 50 is electrically heated by electricconduction through the metallic catalyst portion 52 acting as anelectrical resistant heater up to a temperature high enough, for examplebetween 150° C. and 250° C. with additional temperature increase due tothe provided oxygen, to start catalytic reaction, which occurs typicallybetween 300° C. and 500° C. The catalytic reaction triggers thecatalytic burning inside the main catalyst 50. The emission gas 57 isextracted through a gas exhaust 58.

The catalytic burning inside the conical main catalyst 50 emits IRradiation through the IR transparent enclosure 59, for example made ofquarts glass or aluminium, outside of which water is flowing within awater tube 60, the water being provided through water inlet 61 andreleased through water outlet 62. Alternatively, the water may besubstituted by other liquids in connection with the embodiment. As thewater absorbs the IR radiation efficiently, the wall 64 of the watertube may be made of a light weight material, such as plastic. However,other materials are possible, for example steel or other metals.Preferred is a material which is opaque to IR radiation.

The conical metal mesh of the main catalyst 50 has proven to yield aproper transport of emission gases better than a cylindrical tube. Asthe emission gases are hot, they transfer heat to the water also in thepart above the catalyst 50. In order to provide as much heat as possibleto the water in the water tube 60, the gas supply tube 51 is providedwith a ceramic part 63, thermally isolating coating or surroundingceramic tube, on the part above the catalyst, and, optionally, alsoinside the catalyst.

The electrical wire is connected to the catalyst portion 52 through thewater tube 60 by way of tight flanges 66. The gas flow regulator iselectrically connected 67 to a temperature sensor 68 for measuring theactual temperature of the water in the water tube 60. In addition, theflow regulator 54 is connected 71 to the venturi system 55 and connected70 to a lambda sensor 69 for adapting the burner to optimal catalysisfor highest efficiency and reduced environmental load.

The portable embodiment of the invention is especially suitable forhikers and for military purposes

In FIG. 8, a conical catalyst 50 is illustrated in an embodiment, wherethe catalyst 50 is embedded in a liquid tank 60 for a non-portableapplication, for example for water distribution grid application, as anindustrial liquid warmer, or as a household water heater. The referencenumbers are as in FIG. 5 for likewise elements. The arrangement isdifferent from the apparatus in FIG. 5 in that the catalyst is providedin a horizontal orientation in the bottom of the liquid tank 60, wherethe temperature, normally under heating conditions is substantiallylower than at the top, where the heated liquid is extracted throughliquid outlet 62. For example, the temperature profile of the liquid maybe approximately linearly increasing with height from the catalyticburner. Thus, a typical temperature range between the bottom and the topof the liquid tank is from 25° C. at the bottom due to the cold inletliquid with a temperature of around 15° C. and to around 80° C. at thetop, where liquid is extracted. In order to direct the IR radiationefficiently into the liquid tank 60, there is provided a reflector 72below the IR transparent enclosure 59.

FIG. 9 shows a portable liquid heating bag 75, in a perspective view inFIG. 9 a, illustrating a heating system 74 comprising a heating unit 2with a heating pipe inside a flexible bag 75 the volume 91 of whichfilled with liquid, typically water. For example, the heating bag 75 maybe used for melting snow added into the volume 91 through opening 90 inorder to get water for consumption. The view in FIG. 9 b shows a crosssectional cut through the flexible bag 75 such that an arrangement witha heating pipe surrounded by an outer tube 76 is visible. The outer tube76 has lower openings 77 and upper openings 78 such that water or otherliquid can flow into an interspace between the heating pipe and theouter tube 76. The heating of the water in this interspace createsconvection of the water or other liquid in the interspace such that anefficient circulation is created from the lower openings 77 to the upperopenings 78.

The liquid in the volume 91 may be used for heating other material. Forexample, as illustrated in FIGS. 10 a and 10 b, a likewise system isillustrated, where a liquid box 79 is inserted into the heating bag 75for heating by the water or liquid in the enclosure 75. This liquid boxmay contain an infusion liquid or blood for medical use or othermaterial. The enclosure 75 can be equipped with an upper folding closure80 which can be unfolded for access to the inner volume of theenclosure. Through this folding closure, the liquid box 79 may beinserted or removed from the enclosure 75. Other closing mechanisms, forexample a zip closure, may be used alternatively.

In fact, the liquid heating bag is generally useful when combined withcatalytic burners, also if the burners have other ignition systems thanthe present invention. For example, a piezoelectric ignition system or asystem as disclosed in U.S. Pat. No. 4,886,017 by Viani could be usedalternatively. Thus, useful is a portable liquid heating bag made in aflexible material and having an opening for insertion of a catalyticburner immersed in a liquid inside the container. Preferably, thecatalytic burner has a heating pipe containing the catalyst, where theheating pipe is produced in a material that is transparent for infra-redradiation and fluid-proof for immersion in liquids. Such a catalyticheater may be fastened to an opening in the bag for submersing theheating pipe into the liquid in the bag, where the opening cooperateswith an adapter of the catalytic burner in order to achieve a tightfastening, for example a screw fastening. Preferably, the heating pipe 5is surrounded by an outer tube 76 with lower openings 77 and upperopenings 78 such that water or other liquid can flow into an interspacebetween the heating pipe 5 and the outer tube 76. The heating of thewater in this interspace creates convection of the water or other liquidin the interspace such that an efficient circulation is created from thelower openings 77 to the upper openings 78. The latter embodiment isalso useful in connection with the sterilizer as describe above and withthe body heater as described below.

In FIG. 11 a, a body heater 81 is illustrated with a tube system 82 tobe placed onto the body surface, for example along arms and legs insideclothing. The tube system is connected by circulation tubes 83, 84 to aheat container 85 inside which a heating system 2 according to theinvention is arranged. FIG. 11 b shows the heat container 85 in greaterdetail. A fuel tank 14 provides the necessary fuel for the heating unit2 which warms up liquid inside the heat container 85. By a pump system86, heated liquid enters end exits the heat container through respectiveopenings 87 a, 87 b. Optionally, the pump system may comprise a pumpspeed regulator 88. When the body heater 81 is not in use, the heatcontainer 85 may be closed by a lid 89 after removal of the heating unit2 or after removal of the fuel tank 14, which is illustrated in FIG. 11c. An overpressure valve 93 is provided in order to prevent explosion incase that the liquid is heated over the boiling point.

In fact, the body heater is generally useful when combined withcatalytic burners, also if the burners have other ignition systems thanthe present invention. For example, a piezoelectric ignition system or asystem as disclosed in U.S. Pat. No. 4,886,017 by Viani could be usedalternatively. Thus, useful is a portable body heater having an openingfor insertion of a catalytic burner immersed in a liquid inside thecontainer. Preferably, the catalytic burner has a heating pipecontaining the catalyst, where the heating pipe is produced in amaterial that is transparent for infra-red radiation and fluid-proof forimmersion in liquids. Such a catalytic heater may be fastened to anopening in the bag for submersing the heating pipe into the liquid inthe bag, where the opening cooperates with an adapter of the catalyticburner in order to achieve a tight fastening, for example a screwfastening.

FIG. 12 shows a venturi system and a triggering system for a heatingsystem according to the invention. It should be noticed that the venturisystem is not necessary for the triggering system to function and thetriggering system is not necessary for the advantages of the venturi.However, a combination is preferred due to the optimised performance.

As illustrated in FIG. 12, a venturi system 55 is provided for mix offuel gas 42 and oxygen/air 43. The fuel is provided as evaporated fuelgas 42 through a venturi nozzle 44 and the oxygen/air is added through achannel 45 smoothly bending towards the nozzle exit 49, the channelbeing provided as the space between the concave outer side 46 of thenozzle 44 and the convex inner wall 47 of the surrounding pipe portion48.

The heating pipe 5 encloses a ceramic connection 63 between the venturi44, 48 and the fastening means 94 of the conical main catalyst mesh 50.

An electrode 99 is isolated 100 against a conducting base 101, which iselectrically connected to a holder 102. The holder 102 is electricallyconnected to the electrode 99 via a catalyst part 104 which is heated bycurrent flowing from the electrode 99 through the catalyst part 104 tothe base 101. As the gas mixture is provided at the upper end of thecatalyst mesh 50, the gas has to be transported 104 to the lower, widepart of the catalyst mesh 50. At the lower end, the gas has to changedirection which is achieved with very low flow resistance by a curvedsurface 105, preferably a spherically curved surface. After beingburned, the emission gas 57 leaves the burner between the mesh 50 andthe outer pipe 5. Relative to the main catalyst 50, the surface area ofthe catalyst part 104 is very small, such that only a small current isnecessary to heat the catalyst part 104.

In FIG. 13 a, a gas cartridge 14 is shown. In comprises a container 162closed by a valve cup 163, from which a tube member 164 extends forrelease of gas from the container 162. As will be more obvious from thefollowing, especially FIG: 14 a, the valve cup 163 has a cavity 166,into which a cup insert 165 can be inserted. The upper image, FIG. 13 a,shows the cup insert 165 outside the valve cup 163, and the lower image,FIG. 13 b, shows the cup insert 165 positioned inside the valve cup 163.The cup insert 165 comprises a protection cap 106 covering the tubemember 164 for protection of it. Fastening of the protection cap 106inside the cavity 166 of the valve cup 163 is achieved by a number ofresilient wings 107, which in illustrated in greater detail in FIG. 16a-c.

FIG. 14 a shows the cartridge 14 before insertion of the cup insert 165and FIG. 14 b shows the cartridge 14 after insertion of the cup insert165. The cartridge 14 comprises the container 162 with a container wall108, inside which an absorptive media 109 is located which absorbsliquid gas. When gas is released from the cartridge 14 through tubemember 164 the drop in pressure leads to a further evaporation of gasfrom the liquid gas in the absorptive media 109. The gas travels alongtube 110 into valve 111 and is released through tube member 4.

It should be mentioned that first experiments have revealed that fibrousmaterial in the form of commercially available prior art tampons haveproved efficient liquid gas absorbers. These are efficient to a degreethat proper upside down functioning of the cartridge is guaranteeddespite the fact that the tube 110 can extend farther than half way downinto the gas container and the amount of liquid gas in the containerfills more than half the volume of the container.

FIG. 15 shows the valve 111 in the valve cup 163 in greater detail. Thetube member 164 has a tube wall 112 and an internal channel 113 throughwhich gas is released through opening 113′ at tube end 112′. The releaseof gas is achieved, when the tube member 164 is pressed into the space114 by counteracting the resilient force from the spring 127 (or,alternatively another type of resilient member). The spring 127 pressesthe tube member shoulders 115 against rubber sealing 116 in a seat valveconfiguration. This rubber sealing 116 closes for gas access to thethree release channels 117 a, 117 b, 117 c. Gas finds its way into space114 through tube 110 and pipe 118. The tube member 164 may be pressed adistance into the space 114 such that only the first release channel 117a is open for gas release from the space 114. This leads to gas releaseat a first release rate. If the tube is pressed further into the space,gas is released through the first release channel 117 a and through thesecond release channel 117 b, leading to a faster release rate of thegas. An even further pressing of the tube member into the space 114leads to a release not only through the first 117 a and second 117 brelease channel but also through the third release channel 117 c,implying an even faster release of gas through internal channel 113 oftube member 4. The cross sectional size of the release channels 117 a,117 b, 117 c may be equal or may be varying. In addition, the number ofrelease channels can be different from three in dependence on thedesired number of release steps. The seat valve 111 is gas-tightlysupported and enclosed by a metal surrounding 119 and support cone 120being part of the valve cup 163.

The valve cup 163 has an open ring 121 with a sealing 122 for engagementwith the neck 123 of container 162 as illustrated in FIG. 14 a. Duringproduction, when the valve cup 163 is mounted on the container neck 123,the initially straight side walls 124 of the valve cup 163, as shown inFIG. 15, are deformed into shoulders 126, as shown in FIG. 14 a, forsecure and gas tight fastening of the valve cup 163 to the containerneck 123. These shoulders 126 are used for holding the cup insert 165 inplace, as the resilient wings 107 during insertion slide along the innerside 125 of the open ring 121 and grab into the shoulders 126, which isillustrated in FIG. 14 b.

FIG. 16 a is a side projection of the cup insert 165 in analogy to FIG.13 a, and FIG. 16 b is a top view before removal of the protection cap106. The protection cap 106 has a lower rim 106′, which is not shown inFIG. 16 a. The lower rim 106′ is connected to the outer ring 128 by bars129 which are broken for removal of the protection cap 106, after whichthe cup insert 165 appears as illustrated in FIG. 16 c.

The cup insert 165 also comprises inner threads 130 for connection to agas consuming apparatus, for example via an adapter 131, as illustratedin FIG. 17. The adapter 131 has a first threaded part 132 engaging withthe threads 130 and a second part 133 with outer threads 134 forengagement with cooperating threads in an apparatus. Such an engagementwill be explained in more detail later.

FIG. 18 a-18 e illustrates an assembly sequence for a cartridgeaccording to the invention. In FIG. 18 a, the valve cup 163 with thetube 110 is provided with a sleeve 135 of an absorptive media 109. Thesleeve 135 has an inner tubular channel 136 for accommodation of thetube 110 and with a conical part 138 at the one end 137 for facilitatingthe insertion of the tube 110. FIG. 18 b shows the situation when thetube 110 is accommodated in the sleeve 135. The assembly of the valvecup 163 and the sleeve 135 is inserted into the container 162, asillustrated in FIG. 18 c, and then sealed by deformation of the straightwalls 124 into shoulders 126, which is shown in FIG. 18 d. FIG. 18 eshows an end view of the final assembly.

The absorptive media 169 takes up liquid gas and prevents that liquidgas enters the tube 110 such that only evaporated gas is releasedthrough tube member 164. The absorptive media 109 can be made of variouskinds, however, first prototypes used tampons without superabsorbants.Tampons of the normal commercial type have proven to be suitable forabsorbing all liquid gas efficiently. During filling of liquid gas intothe container 162, the tampon absorbs the liquid and expands, until itfills most of the container, as illustrated in FIG. 2 b.

It should be mentioned that the primary purpose of the invention is inconnection with fuel cartridges. However, aerosol gas cartridges isanother application. If aerosols are desired, the tube 110 may extendeven further into the container 162.

FIG. 19 a illustrates a possible embodiment of an apparatus in the formof a catalytic burner containing a cartridge 14. FIG. 19 b is anenlarged view of part of FIG. 19 a. The outer threads 134 of the adapter133 are engaged with inner threads 140 of the apparatus 1 for mount ofthe cartridge 14 onto the apparatus 1. The tube member 164 extendsthrough a sealing ring 141 to a press member 142 against which the tubemember 164 is pressed when the adapter 133 is screwed far enough intothe apparatus. Screwing the cartridge 14 results in a longitudinaldisplacement of the adapter relative to the threads 140 of the apparatus1 and, consequently, results in a longitudinal displacement of thecartridge 14 relatively to the apparatus 1. If the cartridge 14 isscrewed into the apparatus 1, the tube member 164 is pushed into thespace 114 providing passage between the space 114 through one or more ofthe release channels 117 a, 117 b, 117 c and into the entrance channel143 of the apparatus 1.

In prior art gas valve arrangements or aerosol valve arrangements, thetube member 164 has an outer diameter of 2.76 mm, 3.08 mm, 3.70 mm, 4.70mm, or 5.15 mm. By providing a cartridge with a different diameter ofthe tube member 164, for example 4.00 mm, the cartridge 14 can bedesigned to only function correctly in connection with a certain type ofapparatus.

Practical experiments have shown that a fine adjustment threadingbetween the adapter 133 and the apparatus 1 leads to a smoothlyadjustable gas flow over the diameter of the release opening 117 a, 117b, 117 c. Such release opening can also be produced elongate along thepressing direction, such that a smooth adjustment of the gas flow ratecan be performed over a larger pressing distance.

With reference to FIG. 19 b and FIG. 20, the gas pressure from the gasin the tube member 4, 4′ pushes against rubber ball 44 such that it isdisplaced form its seat 169 for letting gas pass around it into and intonozzle 16 being part of a venturi 55. In case of overheating of theapparatus 1, a bimetallic plate 47 is deformed in its seat 170 due tothe heat and pushes the rubber ball 44 back against the gas flow inorder to reduce the gas flow such that a safe operating temperature canbe assured for the apparatus 1.

As illustrated in FIG. 19 a, the container 2 is protected by a bottomcap 148.

Instead of using the engagement between threads 140 of the apparatus 1and the threads 134 of the adapter 133 for longitudinal distanceadjustment of the cartridge 14 relatively to the apparatus 1, adifferent mechanism may be provided. This is illustrated in FIGS. 20 aand 8 b.

In FIG. 20 a, an embodiment is shown, where a protection tube 151surrounds the cartridge 14 and is fastened to the apparatus 1. FIG. 20 bis an enlarged partial view, where most of the parts of the apparatusare not shown. With reference to FIG. 20 a, an end part 152 of theprotection tube 151 has outer threads 153 engaging with inner threads149 of the end cap 148. By turning the end cap 148, the engagementbetween the threads 149 and 153 displaced the end cap relatively to theprotection tube 151 by which a bottom plate 150 displaces cartridge 14relatively to the apparatus 1. In this case, no cup insert 105 isinserted into the cavity 3′ of the valve cup 3. The adapter 133 of FIG.19 b is substituted by a different adapter 133′, which in the embodimentof FIG. 20 b is fastened to the apparatus 1 in the same way as theadapter in FIG. 19 b, however, as there is no cup insert 165 in theembodiment of FIG. 20 b, the purpose of the adapter is a slidingguidance between a cylindrical part of the valve cup 165 and acylindrical surface of the adapter 133′.

By surrounding the cartridge 14 with a protection tube 4, the cartridge14 is protected against damage from the outside. In addition, anefficient heat exchange can be achieved between the emission gas and theintake air. Furthermore, the cartridge can be heated by the emissiongas, which is relevant in cold regions. These advantages will bedescribed in more detail below.

FIG. 20 b illustrates a situation, where the tube member 164 has beenpressed so far into the space 114 that the first release channel 117 ais just about to connect the space 14 with the inner channel 113 of thetube member 164.

The cartridge is useful for a catalytic burner as disclosed inInternational patent application WO 2007/085251, the disclosure of whichis included herein by reference. In the prior art catalytic burner of WO2007/085251, there is provided a regulator with a valve for release offuel gas operated by an external button. However, in connection with thestepwise regulation mechanism of the cartridge, this regulator can beavoided, because the cartridge itself has a stepwise regulationfunction. All other parts can be retained.

The catalytic process produces a great amount of infra-red radiation,which is being transmitted through the fluid-proof, infrared-transparentmaterial of the heating pipe 5 and into the fluid container 163. Themedium, for example water containing liquid, in the container 163 isexposed to the infra-red radiation that especially heats the medium inthe container 163. In order to ensure an effective utilization of theinfra-red radiation, the container 163 may be provided with a reflectivecoating on the inside in order to reduce the emission of heat throughthe wall of the container 163. Furthermore, it is possible to constructthe container 163 with a heat insulating wall, optionally with amulti-layered structuring as known from thermo-isolated bottles.

The quality of the catalytic process is depending on the amount of gasdelivered to the catalytic burner, as the burner demands differentamounts of gas in dependence of the surrounding temperature and therequired performance of the apparatus 1. The delivered gas rate isadjusted as explained as above in connection with FIG. 19 and FIG. 20.

With a heat insulating container 163 and a handle 51 that is barelyheated, it is difficult to trace the use of such heating system 1 inconnection with military action, because the emission of heat, by thisway, is minimised. A certain kind of emission of heat that implies apotential risk of tracing during application is associated to the heatedemissions (gas, water vapour) from the known catalytic process throughthe exhaust opening 170. To reduce the temperature of the emission gasesthere is provided a counter flow heat exchanger 171 that, at least inpart, encloses the gas cartridge 14 in order to transform heat from theexhaust emissions to the gas in the gas tank. Moreover, the pipeline 169for the emission gas is, at least in part, surrounded by the pipeline161 for the intake air through the inlet port 162. Accordingly, heat istransferred from the emission gases to the gas cartridge 14 and to theintake air, which contributes towards an optimal combustion. In thisconnection it should be mentioned that the gas from the gas cartridge 14during expansion after the nozzle in the venturi system 55 entails acooling of the gas so that absorption of substantial amounts of heatfrom the exhaust is possible.

Emission of heat from the emission gas to the intake gas and the gascartridge 14 contributes towards ensuring an expedient function of theheating system also in very cool surrounding. Therefore, the heatingsystem is well suited for use both in hot and cool areas and due to itsrobust nature it is well suited for use in the military sector.

FIG. 21 illustrates a further embodiment of the catalytic burner,wherein a pressure regulator 146 is implemented in the catalytic burner.The cartridge has a female adapter 197 with an internal tube member 164′for release of fuel from the cartridge 14. The internal tube member 164′of the cartridge 14 is pressed in the direction into the cartridge 14 bya mail adapter 196 such that gas is released through the male adapterinto valve system 198. In valve system 198, a valve member 199 closesfor gas exit into adjacent chamber 195 unless press member 155 pressesagainst valve member 199. In operation conditions, this press member 155presses valve member 199 in the direction of the cartridge such thatfuel gas is released through valve system 198 and into adjacent chamber195. A certain predetermined amount of the gas enters from adjacentchamber 195 into channel 139 and further into the venturi system 55. Thepressure on the valve member 199 is determined by the force of a spring157 against a resilient rubber membrane 194 which holds the press member155 resiliently in position. If the pressure in adjacent chamber 195increases, the press member 155 is resiliently pushed in a directionaway from the cartridge towards spring 157, by which the valve member199 is also moved in a direction away from the cartridge 14 with theresult that the flow through the valve system 198 is reduced. When theadjacent chamber 195 is emptied for gas again through channel 139, thepressure in adjacent chamber 195 decreases, and spring 157 presses pressmember 155 more against the valve member 199, which again increases theflow. This system passively regulates the pressure in adjacent chamber195 and works as a passive flow regulator independent of temperature andindependent of the gas pressure in the cartridge.

As illustrated in FIG. 20 in analogy to FIG. 19 b, the gas pressure fromthe gas pushes against rubber ball 44 such that it is displaced form itsseat 169 for letting gas pass around it into and into nozzle 16. In caseof overheating of the apparatus 1, a bimetallic plate 47 is deformed inits seat 170 due to the heat and pushes the rubber ball 44 back againstthe gas flow in order to reduce the gas flow such that a safe operatingtemperature can be assured for the apparatus 1. Also, the bimetallicdisc 47 is configured to changing shape when the temperature of theheated medium reaches a predetermined temperature, for example 90degrees centigrade. This is achieved by influence of the temperature ofthe heated medium around the infrared transparent tube 5 which is inthermal contact with the bimetallic plate 47 through the metallichousing, which preferably is made of aluminium with a good thermalconductivity. Furthermore, it should be noted that in the situationwhere pipe 5 is not sufficiently surrounded by liquid to take up theirradiated heat from the catalytic burner, the emission gas 173 willhave a higher temperature than under correct operation of the burner.This higher temperature, also, leads to a deformation of the bimetallicplate 47 which results in a reduction or even shut of the gas supply,which is an additional safety measure against overheating of theapparatus. The bimetallic plate, thus, has a triple safety function.

Further details that are illustrated in FIG. 20 are a spring calibratedpressure relief valve 156 as an overpressure safety arrangement, a heatshield 159 preferably with low thermal conductivity, and athereto-isolating ceramic tube shield 171.

FIG. 22 illustrates an improved air intake and emission gas outletsystem with a double tube system for heat recovery around the cartridge14. The heating apparatus 1 itself with the catalytic heater is notshown. Essential for this illustration is the flow 172 of the gas fromthe catalytic heater 1. This gas is not exhausted at the site of thecatalytic heater 1 but returned to the outer wall 162 of the cartridge14, which is illustrated by arrows 172, 173. The hot exhaust indicatedby arrow 172 is led along the outer side of the wall 2 of the cartridge14, which is illustrated by arrows 173 by which the emission gas 172gradually looses its heat towards the bottom plate 150 of the end cap148, where the emission gas 172 is released to atmosphere. The outerwall 108 of the cartridge 14 is preferably made of a material withproper heat conduction, for example aluminium. Thus heat is transferredto the gas inside the cartridge 14, which improves the gas flow out ofthe tube member 164 of the cartridge 14. It also counteracts the loss ofheat due to evaporation/expansion of the gas when leaving the cartridge14.

During flow of the hot emission gas along the wall 162, the gas 172 iscooled by the heat exchange with the wall 162 before being released toatmosphere through exit openings in the end cap 148, which isillustrated by arrows 174. As these openings are directed radiallyoutwards from the end cap 148, mixing with the surrounding air is almostinstantaneous, such that infrared tracing of the heater is madedifficult due to a reduced and blurred signal because of the mixing withthe cold surrounding air.

As an additional means to recover the heat from the catalytic burning,air taken in for catalytic burning flows—illustrated by arrow 175—intothe tube 161 and is heated by the emission gas 172 through a heatconducting partition wall 176, before it flows—illustrated by arrow177—to the catalytic heater. This measure reduces the temperature of theemission gas further, which minimises the possibility of thermallytracing the heater in military operations.

Though use of the cartridge above has been explained above in connectionwith hand held, portable catalytic heaters, this is in no way limitingfor the invention. Such a cartridge may be used as an aerosol cartridgeas a substitution for prior art cartridges in the different fields ofapplication.

When used in connection with a catalytic heater, the application mayextend into a heater for liquid in a water-tight flexible bag in orderto heat up liquid in the bag by the heater. For example, a bag may beprovided for heating water or other liquids, such as

-   -   water for cleaning,    -   medical infusion liquids,    -   water used in body-tight circulation systems for heating human        bodies, optionally incorporated in the garment/clothing of a        person,    -   general water provision by melting snow in a bag or other type        of container.

1-22. (canceled)
 23. A catalytic heating system (1) comprising a maincatalyst (20, 50) for flameless catalytic burning of fuel gas and atriggering system for initiating the catalytic burning, the triggeringsystem comprising an electrical power source electrically connected toan electrically conducting, separate metallic catalyst portion (104) forcausing electrical current to flow through the catalytic portion (104)and thereby heating the catalyst portion to a temperature necessary fortriggering the catalytic burning at the catalyst portion.
 24. Acatalytic heating system according to claim 23, wherein the metalliccatalyst portion (104) is substantially smaller than the main catalyst(50).
 25. A catalytic heating system according to claim 24, wherein themetallic catalyst portion (104) through which current flows has a widthand a height and a length, each of which is smaller than 1 mm.
 26. Acatalytic heating system according to claim 23, wherein the maincatalyst (20, 50) is a metallic mesh.
 27. A catalytic heating systemaccording to claim 26, wherein the main catalyst (50) is a tubular meshwith varying diameter.
 28. A catalytic heating system according to claim27, wherein the main catalyst is a tubular mesh (50) in the shape of atruncated cone.
 29. A catalytic heating system according to claim 23,wherein a venturi system (17, 55) is provided for mix of fuel gas andoxygen, the venturi system comprising a venturi nozzle (16, 44) with anozzle exit (49), through which fuel gas is provided, and a channel (45)around the venturi nozzle, the channel being formed between the outerwall (75) of the venturi nozzle and a pipe portion (47) surrounding thenozzle, the outer wall of the venturi nozzle being concave and thesurrounding pipe portion being convex to form a smoothly bending channeltowards the venturi nozzle exit.
 30. A catalytic heating systemaccording claim 23, wherein the system is a portable system withintegrated fuel tank (162) and comprising a handle (4) and an inextension hereof arranged heating pipe (5) containing the catalyst (20,50), where the heating pipe is produced in a material that istransparent for infra-red radiation and fluid-proof for immersion inliquids.
 31. A catalytic heating system according to claim 23, furthercomprising a heat exchanger (171) between a fuel tank (162) and anexhaust pipe system for heat exchange between emission gas from thecatalytic burning and a wall of the fuel tank, the heat exchangercomprising a flow path for leading the burned gas from the catalyst pastthe fuel tank.
 32. A catalytic heating system according to claim 23,wherein the catalyst (20, 50) is surrounded by a fluid-proof, infra-redtransparent enclosure (5) immersed in a liquid tank for heating ofliquid in the liquid tank (3) by the infrared radiation from thecatalytic burning by the catalyst.
 33. A catalytic system according toclaim 32, wherein the catalyst is elongate and extends horizontally orsubstantially horizontally in a bottom area of the tank.
 34. A catalyticsystem according to claim 32, wherein the main catalyst is a conicalmetallic mesh with a large end towards a bottom of the enclosure (5) anda narrow end of the cone arranged towards a gas exhaust.
 35. A catalyticsystem according to claim 32, further comprising a flow path for intakeair and a heat exchanger for heat exchange between hot, burned gas fromthe catalyst and intake air for the catalyst.
 36. A catalytic systemaccording to claim 28, wherein at a lower, wide part of the catalystmesh there is provided a curved surface 105 for change of direction offuel gas mixture.
 37. A catalytic heating system according claim 23,further comprising a cartridge containing gas with or without aerosols,the cartridge (14) comprising a container (162) for containing the gasand comprising a valve arrangement (164, 112, 113, 114, 115, 116, 127,117 a, 117 b, 117 c) with a tube member (164) for release of gas with orwithout aerosols from the container (162) through a channel in the tubemember, the valve arrangement comprising and a resilient member (127)providing a resilient force against the tube member (164) directed awayfrom the container, the tube member (164) having an inner channel (113)for release of gas from the container (162, 163) through the channel(113) when the tube member (164) is pressed against the resilient forcea distance along a pressing direction towards the inside of thecontainer.